1. Technical Field
The invention relates to the time shifting of television broadcast signals. More particularly, the invention relates to the real time capture, storage, and display of television broadcast signals and the transfer and playback of the television broadcast signals from a DVD player/recorder.
2. Description of the Prior Art
The Video Cassette Recorder (VCR) has changed the lives of television (TV) viewers throughout the world. The VCR has offered viewers the flexibility to time shift TV programs to match their lifestyles.
The viewer stores TV programs onto magnetic tape using the VCR. The VCR gives the viewer the ability to play, rewind, fast forward and pause the stored program material. These functions enable the viewer to pause the program playback whenever he desires, fast forward through unwanted program material or commercials, and to replay favorite scenes. However, a VCR cannot both capture and play back information at the same time.
One approach to solving this problem is to use several VCRs. For example, if two video tape recorders are available, it might be possible to Ping-Pong between the two. In this case, the first recorder is started at the beginning of the program of interest. If the viewer wishes to rewind the broadcast, the second recorder begins recording, while the first recorder is halted, rewound to the appropriate place, and playback initiated. However, at least a third video tape recorder is required if the viewer wishes to fast forward to some point in time after the initial rewind was requested. In this case, the third recorder starts recording the broadcast stream while the second is halted and rewound to the appropriate position. Continuing this exercise, one can quickly see that the equipment becomes unwieldy, unreliable, expensive, and hard to operate, while never supporting all desired functions. In addition, tapes are of finite length, and may potentially end at inconvenient times, drastically lowering the value of the solution.
The use of digital computer systems to solve part of this problem has been suggested. U.S. Pat. No. 5,371,551 issued to Logan et al., on Dec. 6, 1994, teaches a method for concurrent video recording and playback using a fixed length circular buffer. It presents a microprocessor controlled broadcast and playback device. The device compresses and temporarily stores video data onto a hard disk. The processor requirements for keeping up with the high video rates is expensive and problematic. The microprocessor must be extremely fast to keep up with the incoming and outgoing video data. Further, the circular buffer is meant to function as a delay circuit and does not take into account storing an entire program for longer than the length of the circular buffer.
More recently, digital videos recorders (DVR) have emerged in the marketplace that are based on structures beyond what was previously conceived. One example is U.S. Pat. No. 6,233,389 owned by the Applicant. There are a number of technology trends in force today that are continuing to expand the opportunities for DVR functionality. One such trend is the ability to record data onto a recordable DVD as well as a recordable CD. Currently, DVDs offer a platform that can store up to 15.9 GBs of video and audio data on a single disc.
Although video rates can be highly variable, the average five GB single-sided DVD translates to approximately two hours of video. As the capacity of recordable DVDs increases, the capability to use the media to store broadcast audio and video program material becomes more cost-effective. Even with the lower storage capacities of current recordable DVDs, recordable and pre-recorded DVDs still offer an opportunity to extend the storage and playback capabilities of a DVR.
Some VCR manufacturers have combined dual VCRs into one set-top box in order to facilitate easy transfer of content from one VCR to another. Other manufacturers have integrated DVD players into their VCR set-top boxes in an attempt to offer to two playback mediums.